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Re: Tech Discussions on the Multitrack Media (issue-152)

From: Silvia Pfeiffer <silviapfeiffer1@gmail.com>
Date: Fri, 25 Feb 2011 13:06:31 +1100
Message-ID: <AANLkTi=SxuJO0tasGV1zpg+t4L1aeT9jpP1tomq=zSG9@mail.gmail.com>
To: David Singer <singer@apple.com>
Cc: Bob Lund <B.Lund@cablelabs.com>, "public-html@w3.org" <public-html@w3.org>
On Fri, Feb 25, 2011 at 12:36 PM, David Singer <singer@apple.com> wrote:
>
> On Feb 24, 2011, at 17:29 , Silvia Pfeiffer wrote:
>
>>
>>
>> When you talk about videos that are slide shows, are you actually
>> talking about videos or about a sequence of images (photos) that are
>> also sparse along the timeline, so not really "moving images"? If they
>> are encoded as video, it would be impossible to distinguish the data
>> as a sequence of photos. The other case - basically an "image track"
>> is not something we've ever discussed before and is not something that
>> all containers have formats for FAIK.
>
> I mean a video track where the frame rate is like 1 frame every 10 seconds.  Many, or even most, containers can express this, I think.
>
>> As for chapter images - I am not sure how they are encoded in
>> QuickTime/MPEG, so if you know, please share. I would have thought
>> that a text track with image urls could be sufficient for this.
>
>
> An obvious choice is as above, using an I-frame-only coding (e.g. JPEG).


Interesting... not quite the most efficient way to encode, but it
certainly works.

In this case I would probably think that a chapter text track is
sufficient and it can then load a frame from the "chapter video track"
as the image. This can even be done using a Canvas.

Cheers,
Silvia.
Received on Friday, 25 February 2011 02:07:23 GMT

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